The more transparent the filament the better is the fleece, and its value is impaired by the transparency being different in the same fleece, or, as often happens, in the same filament; while that which possesses fineness with a close ground, pureness, elasticity, colour, tenacity, and not much pitch-mark, is the most esteemed, and preferred by the manufacturer. Wethers have considerably more wool than ewes. In every fleece there are several qualities, even so many as nine different sorts, which are all separated from each other in England by men called woolstaplers, who are appointed for the purpose, and sworn to do justice between the grower, and the merchant or manufacturer. In this manner the latter obtains, without trouble or risk, the very kind which he knows will suit his purpose; for though the sorter, surrounded by a number of baskets, divides the wool according to its properties without the slightest hesitation, and with a rapidity truly surprising, yet such is the amount of the dexterity acquired by practice, that a mistake seldom occurs, and his judgment can as rarely be disputed. (31.) _Structure and properties of Hair and Wool._--Each hair is composed of a number of filaments, or smaller hairs, ranged side by side, and this we can perceive without the slightest trouble, from the tendency it sometimes has to unravel at the apex; and again, by drawing a hair through the fingers from point to root, when we feel a roughness occasioned by projecting filaments, which only proceed a certain distance up the trunk, the longest being most internal. Pl. V. Fig. 5, _e_, exhibits those points in a hair considerably magnified. These projections, or serrations, which vary in number in different specimens of wool, are what it depends on for its felting properties. They are sharper and more numerous in felting wools than in others, and the better the felting properties of the wool, the more numerous the curls; because what induces curling on the animal's back leads to felting in the hands of the manufacturer. In felting, these projections catch one upon another, and occasion the hair to move in one direction, which is invariably root foremost, as we perceive on giving it a twirling motion between the finger and thumb; and it is only by the union of curve and serration, that felting can be accomplished certainly and perfectly.